
var canvas = document.getElementById("cas");
var ocas = document.createElement("canvas");
var octx = ocas.getContext("2d");
var ctx = canvas.getContext("2d");
ocas.width = canvas.width = window.innerWidth;
ocas.height = canvas.height = window.innerHeight;
var bigbooms = [];
var myAudio = new Audio();

//js执行入口
window.onload = function(){
    initAnimate()
}

//播放烟花爆炸音效
async function playFireEffect(){
    myAudio.src = "fire.mp3"
    myAudio.play()
    myAudio.loop = false;
}

//播放烟花升起的音效
async function playUpEffect(){
    document.getElementById("up").play();
}

function initAnimate(){
    drawBg();
    lastTime = new Date();
    setTimeout(animate(),randomTime);
}

var lastTime;
var createRamdomTime = true;
var randomTime;

//删除位于队列前部分的所有空元素
//shift = get rid of : to remove sth such as a dirty mark
function safelyShiftAllNull(arr)
{
    while(arr[0]==null)
    {
        arr.shift()
    }
}

function animate(){
    ctx.save();
    ctx.fillStyle = "rgba(0,5,24,0.1)";
    ctx.fillRect(0,0,canvas.width,canvas.height);
    ctx.restore();

    var newTime = new Date();
    if(createRamdomTime)
    {
        var randomNumber = Math.floor((Math.random()*5)+1)*1000;
        console.log(randomNumber);
        randomTime = randomNumber +(window.innerHeight-767)/2
        createRamdomTime = false;
    }
    if(newTime-lastTime>randomTime){
        createRamdomTime = true;
        var random = Math.random()*100>2?true:false;
        var x = getRandom(canvas.width/5 , canvas.width*4/5);
        var y = getRandom(50 , 200);
        if(random){
            var bigboom = new Boom(getRandom(canvas.width/3,canvas.width*2/3) ,2,"#FFF" , {x:x , y:y});
            bigbooms.push(bigboom)
        }
        else {
            var bigboom = new Boom(getRandom(canvas.width/3,canvas.width*2/3) ,2,"#FFF" , {x:canvas.width/2 , y:200} , document.querySelectorAll(".shape")[parseInt(getRandom(0, document.querySelectorAll(".shape").length))]);
            bigbooms.push(bigboom)
        }

        lastTime = newTime;

        safelyShiftAllNull(bigbooms)
    }

    stars.foreach(function(){
        this.paint();
    })

    drawMoon();

    bigbooms.foreach(function(index){
        var that = this;
        if(!this.dead){
            this._move();
            this._drawLight();
        }
        else{
            this.booms.foreach(function(index){
                if(!this.dead) {
                    this.moveTo(index);
                }
                else if(index === that.booms.length-1){
                    bigbooms[bigbooms.indexOf(that)] = null;
                }
            })
        }
    });
    
    raf(animate);
}

function drawMoon(){
    // var city = document.getElementById("city");
    // var citycenterX = canvas.width-400 , citycenterY = 600 , citywidth = 280;
    // if(city.complete){
    //     ctx.drawImage(city, 0, canvas.height-258)
    // }

    var moon = document.getElementById("moon");
    var centerX = canvas.width-200 , centerY = 100 , width = 80;
    if(moon.complete){
        ctx.drawImage(moon , centerX , centerY , width , width )
    }
    else {
        moon.onload = function(){
            ctx.drawImage(moon ,centerX , centerY , width , width)
        }
    }
    var index = 0;
    for(var i=0;i<10;i++){
        ctx.save();
        ctx.beginPath();
        ctx.arc(centerX+width/2 , centerY+width/2 , width/2+index , 0 , 2*Math.PI);
        ctx.fillStyle="rgba(240,219,120,0.005)";
        index+=2;
        ctx.fill();
        ctx.restore();
    }
    
}

Array.prototype.foreach = function(callback){
    for(var i=0;i<this.length;i++){
        if(this[i]!==null) callback.apply(this[i] , [i])
    }
}

var raf = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function (callback) { window.setTimeout(callback, 1000 / 60); };

canvas.onclick = function(){
    var x = event.clientX;
    var y = event.clientY;
    var bigboom = new Boom(getRandom(canvas.width/3,canvas.width*2/3) ,2,"#FFF" , {x:x , y:y});
    bigbooms.push(bigboom)
}

var Boom = function(x,r,c,boomArea,shape){
    this.booms = [];
    this.x = x;
    this.y = (canvas.height+r);
    this.r = r;
    this.c = c;
    this.shape = shape || false;
    this.boomArea = boomArea;
    this.theta = 0;
    this.dead = false;
    this.ba = parseInt(getRandom(80 , 200));
    this.playFlag = true
}

Boom.prototype = {
    _paint:function(){
        ctx.save();
        ctx.beginPath();
        ctx.arc(this.x,this.y,this.r,0,2*Math.PI);
        ctx.fillStyle = this.c;
        ctx.fill();
        ctx.restore();
    },

    //烟花升起/文字移动
    _move:function(){
        var dx = this.boomArea.x - this.x , dy = this.boomArea.y - this.y;
        this.x = this.x+dx*0.01;
        this.y = this.y+dy*0.01;

        if(this.playFlag)
        {
            playUpEffect()
        }
        if(Math.abs(dx)<=this.ba && Math.abs(dy)<=this.ba){
            if(this.shape){
                this._shapBoom();
            }
            else this._boom();
            this.dead = true;
            this.playFlag = true
        }
        else {
            this._paint();
            this.playFlag = false
        }
    },
    _drawLight:function(){
        ctx.save();
        ctx.fillStyle = "rgba(255,228,150,0.3)";
        ctx.beginPath();
        ctx.arc(this.x , this.y , this.r+3*Math.random()+1 , 0 , 2*Math.PI);
        ctx.fill();
        ctx.restore();
    },

    //烟花爆炸
    _boom:function(){
        var fragNum = getRandom(30 , 200);
        var style = getRandom(0,10)>=5? 1 : 2;
        var color;
        if(style===1){
            color = {
                a:parseInt(getRandom(128,255)),
                b:parseInt(getRandom(128,255)),
                c:parseInt(getRandom(128,255))
            }
        }

        var fanwei = parseInt(getRandom(300, 400));
        for(var i=0;i<fragNum;i++){
            if(style===2){
                color = {
                    a:parseInt(getRandom(128,255)),
                    b:parseInt(getRandom(128,255)),
                    c:parseInt(getRandom(128,255))
                }
            }
            var a = getRandom(-Math.PI, Math.PI);
            var x = getRandom(0, fanwei) * Math.cos(a) + this.x;
            var y = getRandom(0, fanwei) * Math.sin(a) + this.y; 
            var radius = getRandom(0 , 2)
            var frag = new Frag(this.x , this.y , radius , color , x , y );
            this.booms.push(frag);
        }
        playFireEffect()
    },

    //文字爆炸
    _shapBoom:function(){
        var that = this;
        putValue(ocas , octx , this.shape , 5, function(dots){
            var dx = canvas.width/2-that.x;
            var dy = canvas.height/2-that.y;
            for(var i=0;i<dots.length;i++){
                color = {a:dots[i].a,b:dots[i].b,c:dots[i].c}
                var x = dots[i].x;
                var y = dots[i].y;
                var radius = 1;
                var frag = new Frag(that.x , that.y , radius , color , x-dx , y-dy);
                that.booms.push(frag);
            }
        })
    }
}

function putValue(canvas , context , ele , dr , callback){
    context.clearRect(0,0,canvas.width,canvas.height);
    var img = new Image();
    if(ele.innerHTML.indexOf("img")>=0){
        img.src = ele.getElementsByTagName("img")[0].src;
        imgload(img , function(){
            context.drawImage(img , canvas.width/2 - img.width/2 , canvas.height/2 - img.width/2);
            dots = getimgData(canvas , context , dr);
            callback(dots);
        })
    }
    else {
        var text = ele.innerHTML;
        context.save();
        var fontSize =200;
        context.font = fontSize+"px 宋体 bold";
        context.textAlign = "center";
        context.textBaseline = "middle";
        context.fillStyle = "rgba("+parseInt(getRandom(128,255))+","+parseInt(getRandom(128,255))+","+parseInt(getRandom(128,255))+" , 1)";
        context.fillText(text , canvas.width/2 , canvas.height/2);
        context.restore();
        dots = getimgData(canvas , context , dr);
        callback(dots);
    }
}

function imgload(img , callback){
    if(img.complete){
        callback.call(img);
    }
    else {
        img.onload = function(){
            callback.call(this);
        }
    }
}

function getimgData(canvas , context , dr){
    var imgData = context.getImageData(0,0,canvas.width , canvas.height);
    context.clearRect(0,0,canvas.width , canvas.height);
    var dots = [];
    for(var x=0;x<imgData.width;x+=dr){
        for(var y=0;y<imgData.height;y+=dr){
            var i = (y*imgData.width + x)*4;
            if(imgData.data[i+3] > 128){
                var dot = {x:x , y:y , a:imgData.data[i] , b:imgData.data[i+1] , c:imgData.data[i+2]};
                dots.push(dot);
            }
        }
    }
    return dots;
}

function getRandom(a , b){
    return Math.random()*(b-a)+a;
}


var maxRadius = 1 , stars=[];
function drawBg()
{
    for(var i=0;i<300;i++)
    {
        var r = Math.random()*maxRadius;
        var x = Math.random()*canvas.width;
        var y = Math.random()*2*canvas.height - canvas.height;
        var star = new Star(x , y , r);
        stars.push(star);
        star.paint()
    }
}

var Star = function(x, y, r)
{
    this.x = x; this.y=y; this.r=r;
}
Star.prototype = 
{
    paint:function()
    {
        ctx.save();
        ctx.beginPath();
        ctx.arc(this.x , this.y , this.r , 0 , 2*Math.PI);
        ctx.fillStyle = "rgba(255,255,255,"+this.r+")";
        ctx.fill();
        ctx.restore();
    }
}

var focallength = 250;
var Frag = function(centerX , centerY , radius , color ,tx , ty){
    this.tx = tx;
    this.ty = ty;
    this.x = centerX;
    this.y = centerY;
    this.dead = false;
    this.centerX = centerX;
    this.centerY = centerY;
    this.radius = radius;
    this.color = color;
}

Frag.prototype = {
    paint:function(){
        ctx.save();
        ctx.beginPath();
        ctx.arc(this.x , this.y , this.radius , 0 , 2*Math.PI);
        ctx.fillStyle = "rgba("+this.color.a+","+this.color.b+","+this.color.c+",1)";
        ctx.fill()
        ctx.restore();
    },
    moveTo:function(index){
        this.ty = this.ty+0.3;
        var dx = this.tx - this.x , dy = this.ty - this.y;
        this.x = Math.abs(dx)<0.1 ? this.tx : (this.x+dx*0.1);
        this.y = Math.abs(dy)<0.1 ? this.ty : (this.y+dy*0.1);
        if(dx===0 && Math.abs(dy)<=80){
            this.dead = true;
        }
        this.paint();
    }
}